Help plz

My baby Had low fever flu n coughing last week it’s fne now, but from yesterday she is having stomach upset, n vomiting not too much like vomiting just once n running diaper 3 times, she is 15 months, doc said she l b fne witching few days her molar teeths r coming.i think her lower ones r coming.
last month when her upper molar teeths were coming she had on n off fever for 3 days, but this time vomiting n stomach upset is bothering.
i have already changed her diet for stomach upset giving her bananas n rice cereals.
doctor asked me to keep her hydrated. She is otherwise eating fne n is active but running diapers n vomitting is upsetting me, also slight fever I m giving calpol foe fever.
should I just wait, or wht to do?
i m so confused
Plz help n suggest wht to do?